Industrial wastewater containing synthetic dyes poses a major environmental and health concern because these pollutants are toxic, stable, and difficult to remove using conventional treatment methods. Among various photocatalysts, zinc oxide (ZnO) is extensively studied due to its low cost, chemical stability, non-toxic nature, and strong oxidative potential. Nevertheless, its practical application is restricted by a wide band gap and fast recombination of photo-generated charge carriers, which reduce activity under visible light. Recent progress shows that forming ZnO- based nanocomposites effectively overcomes these limitations by improving light absorption, suppressing charge recombination, and increasing reactive surface sites.
